Process for forming bulk yarns from continuous filament webs



Nov. 24, 1970 ,sTEvE,;|sON 3,541,653

PROCESS FOR FORMING BULK YARNS FROM CONTINUOUS FILAMENT WEBS Filed Dec. 19, 1%8

li/1mm Mm FIG.2. FIG.3.

[FORMlNG MATT OF CONTINUOUS BULKABLE FILAMENTS I STITCHING THE MATT LONG|TUD|NALLY CUTTING THE MATT BETWEEN ROWS OF STITCHES BULKING THE FILAMENTS TO COVER THE STITCHESJ FIG, 4. INVENTOR.

PHILIP J. STEVENSON ATTORNEY United States Patent 01 iice 3,541,653 Patented Nov. 24, 1970 3,541,653 PROCESS FOR FORMING BULK YARNS FROM CONTINUOUS FILAMENT WEBS Philip J. Stevenson, Durham, N.C., assignor to Monsanto Company, St. Louis, Mo., a corporation of Delaware Filed Dec. 19, 1968, Ser. No. 785,255 Int. Cl. D023 1/12 US. Cl. 28-77 11 Claims ABSTRACT OF THE DISCLOSURE A high density bulked yarn having a bulk density of less than 0.050 g./cm. is formed by stitching a matt comprised of bulkable synthetic continuous filaments to form a plurality of aligned seams by cutting the matt between the seams to form individual yarns and subsequently bulking the synthetic filaments locked in the seams by contacting the yarns with a heated fluid. Upon being bulked, the synthetic filaments curl to cover the seam.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to a bulked yarn and, more particularly, to a bulked yarn which is made by the seaming of a non-woven batt of synthetic bulkable filaments and by the subsequent cutting and bulking of the filaments.

Description of prior art SUMMARY OF THE INVENTION This invention relates to the Arachne process which is currently used in the making of blankets and other textile fabrics where the conventional weaving and knitting steps are omitted. The Arachne process includes the forming of a matt generally from staple fibers and the sewing of the batt along various directions to give the matt strength. A typical product of the Arachne process is disclosed in US. Pat. 3,365,918 which produces a simulated nonwoven corduroy fabric.

In the present invention, yarn strength is developed not by the conventional drafting and twisting of a fiber bundle which results in a great loss of volume but by the stitching of a fine sewing thread through a fibrous matt. As a result of the superior volume to weight ratio of the yarns, a savings in material of up to 20 percent can be obtained.

Therefore, an object of this invention is to provide high bulk yarns. Another object of this invention is to form high bulk yarns by sewing a series of threaded seams in the machine direction of a continuous filament matt and by subsequently slitting the matt between adjacent threaded seams.

A further object of this invention is to form high bulk yarns from matts comprised of bulkable synthetic continuous filaments.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a matt of bulkable synthetic filaments having a series of substantially parallel threaded seams;

FIG. 2 is an enlarged view of a yarn having been cut from the seamed matt of FIG. 1 prior to bulking;

FIG. 3 is the yarn of FIG. 2 after said yarn has been subjected to a bulking treatment; and

FIG. 4 is a flow chart identifying the steps of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred process for forming the non-woven web is carried out on a continuous basis as set forth in US. application Ser. No. 646,720. In that application, the filaments having been spun and laid down onto a belt was subsequently bonded by gaseous means; however, permanent bonding does not form a part of this invention and the matt is ultimately left unbonded. For ease of handling the non-woven matt, a weak water soluble cellulosic gum may be applied to the matt which is subsequently removed after seaming by Washing in a hot water bath. The filaments as shown are bi-component and may be freshly spun from two polyamides having different heat shrinkage characteristics, two polyesters having differential heat shrinkage characteristics or a polyester and a polyamide having different heat shrinkage characteristics. Also, the bicomponent filament may be formed at a prior time and supplied to the aspirator mechanism as shown in the mentioned application by means of a bobbin. Where the bicomponent filaments are formed at a prior time, two acrylonitrile-based polymers having different heat shrinkage characteristics may be used.

The matt which is comprised of continuous bicomponent synthetic filaments and which has been formed on a conveyor belt is moved by the conveyor belt to a bank of sewing needles which are positioned across the width of the matt. Each of the needles is adapted to sew a seam along the length of the matt with the seams being separated from each other a distance, the distance being determined by the ultimate denier of the produced yarn. The matt having the seams formed along the length thereof is then fed to a slicer which is adapted to cut the matt equidistantly between adjacent seams. The yarns may then be bulked, wound onto bobbins or wound onto a beam. Where bulking is to take place immediately after the formation of the yarns, the yarns are contacted with a heated gaseous medium or submerged in hot water at a temperature of at least F. whereupon the portions of the bicomponent fibers having the greatest heat shrinkage characteristics causes the filaments to bend back on themselves and to cover the threaded seam.

In reference to FIG. 1, matt 10 is comprised of a plurality of bicomponent filaments 11 which are laid down in a manner as herein set forth. Matt 10 is provided with seams 12 which are comprised of a plurality of linearly interlocking stitches 13. As shown in FIG. 1, the preferred orientation of filaments 11 is normal to the direction of seams 12.

The density of the bulked yarns of this invention vary from 0.02 to 0.10 gm./cm. In comparison, cotton yarns generally have densities of between 0.45 and 1.28 gms./cm. and worsted yarns have densities ranging generally between 0.38 and 0.73 gm./cm. Turbo-stapled acrylic fiber yarns after bulking have densities of about 0.25 gm./cm. It can be seen that considerable savings of material can be made by following the teachings of this invention.

For some end use applications, elastic yarns find utility. The bulked yarns of this invention are easily provided with the required elasticity by substituting threads comprised of an elastomeric urethane rubber or the like for the mentioned threads. Such threads are generally stitched into the matt under tension to increase the bulk density of the yarn.

3 EXAMPLE 1 Continuous bicomponent nylon filaments, denier, were spun from an extruder in the conventional manner. The filaments were passed through an aspirator jet and laid randomly onto a foraminous conveyor belt. The weight of the matt was approximately 1.5 oz./yd. The matt was passed through a bank of sewing needles which formed a threaded seam in the machine direction every 0.40 in. The stitching thread was #40 cotton [approximately 320 denier, tenacity 2.1 lbs., 3 grams per denier]. The stitching needles were set to sew approximately six stitches 1n the matt per linear inch in the machine direction. The seamed matt was comprised of 82% by weight of the bicomponent continuous nylon filaments and 18% by weight of the sewing thread. A seamed matt was then passed through cutters which slit the matt equidistantly between each of the seams.

The density of the yarn before bulking was 0.089 gm./cm. The yarn was then passed through a hot water bath, the water being heated to approximately 212 R, where bulking occurred. After bulking and drying, the density of the yarn was 0.035 gm./cm. The denier of the bulked yarn was 5,670 and the bulked yarn had a tenacity of 4.81 lbs. and a tenacity per denier of 0.38.

EXAMPLE II synthetic nylon fibers, 17% by weight of the sewing thread.

After slitting the density before bulking of the yarn was 0.102 gm./cm. and the density after bulking was 0.029 gm./cm. The bulked yarn had a denier of 5,000, a bulked yarn tenacity of 3.95 lbs. and atenacity in grams per denier of 0.36. It can be seen that by orienting the filaments slightly in the direction normal to the machine direction, the density after bulking decreases.

The specification has set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a descriptive sense only and not for the purposes of limitation only, the scope of the invention being defined in the claims.

I claim:

1. A process for making a high bulked textile yarn comprising the steps of:

(a) forming a matt of continuous synthetic bulkable filaments, said filaments having a latent tendency to curl when subjected to a bulking treatment;

(b) forming at least two seams along the length of said matt in a given direction, each said seam being comprised of interconnected individual stitches of thread being effective to lock said synthetic filaments mechanically along said seam length;

(0) cutting said matt between adjacent seams longitudinally with respect to said seams to form individual yarns; and

(d) bulking said bulkable synthetic filaments whereby said seam is substantially covered by said bulked filaments.

2. The process of claim 1 wherein the preferred orientation of said synthetic filaments comprising said matt is in.the direction being normal to said seams.

3. The process of claim 2 wherein said bulkable filaments are bicomponent.

4. The process of claim 3 wherein said bicomponent filaments are heat bulkable.

5. The process of claim 4 wherein said bicomponent filaments are bulked by being contacted with water being heated at least to F.

6. The process of claim 4 wherein said bicomponent filaments are bulked by being contacted with a hot gas being heated at least to 150 F.

7. The process of claim 4 wherein said bicomponent filaments are comprised of two polyamides having different heat shrinkage characteristics.

8. The process of claim 4 wherein said bicomponent filaments are comprised of two polyesters having different heat shrinkage characteristics.

9. The process of claim 4 wherein said bicomponent filaments are comprised of two acrylonitrile based polymers having diiferent heat shrinkage characteristics.

10. The process of claim 1 wherein said yarn has a bulk density of less than 0.100 gm./cm.

11. The process of claim 1 wherein said seams consist of elastic yarns.

References Cited UNITED STATES PATENTS 520,400 5/1894 Cattlow 2877 1,769,970 7/1930 Silverman 2877 3,058,193 10/1962 Mauersberger et a1: 2877 3,330,896 7/1967 Fujita et a1 28-72.17 3,365,918 l/1968 Hughes 66-85 ROBERT R. MACKEY, Primary Examiner US. Cl. X.R. 

